Apparently, data can still be recovered from media fragments over 0.5 cm, hence why we shred to below this size.
I would expect that you have to quantify what risk the data is and then consider the media before deciding how safe you want to be. Most of our data is:-
- Within a database (so some scrambling/compression there)
- Multiple allocations of space shared withint he database (fragmentation)
- External logical disks formed from virtual slices of 12 disks in a RAID5 set
.... yet, we still shred these disks if any are replaced because we handle personal and financial data. Paranoia? Possibly. Of course this could be fuelled by the manufacturers of the shredders, if one was to be cynical
Robin